skrev i meddelandet news:4Pm37.178065$%i7.116159417@news1.rdc1.sfba.home.com... > >Instantiate Direct_IO with constrained subtypes of Matrix for the types > >of interest. > i.e. > >My own ideas is to create separate databases for all eight databases > >that uses DB (CAR_DB, BOAT_DB, HOUSE_DB...) with specified values for > >MATRIX, but that seems like a lot of work and not very objectoriented. > If you are doing direct IO all the records in a given file need to > be the same size anyway, so it certainly is reasonable to instantiate > Ada.Direct_IO once for each of the eight database files. Did the > old program actually mix different size records in a single file? How > did it know where to look for record N? No, the program created a separate file for each database. The big problem for me with this program is that the part about the database(s) i totally uncommented and there is no documentation what so ever. And the person who originally designed is gone since 13 years ago and probably doesn�t remember anything. > As for OO, if you have a > root Matrix tagged type make it abstract, then each of the eight > children should have its own overide of its input/output routines > using the appropriate instantiation. Sounds like a great concept /Magnus magnus-s@dsv.su.se